In the past, fibrous structures, such as paper towels, have been commonly utilized in combination with liquid cleaning compositions to clean windows, mirrors, countertops, and other hard surfaces. Known paper towels typically provide cleaning performance primarily by absorption of soil laden fluid into the pores of the paper towel, consequently, the cleaning performance of known paper towels is limited by the ability of the paper towels to absorb and retain the soil laden fluid.
Improved removal of soil from various surfaces continues to be a big consumer need. Formulators have attempted to enhance the soil removal properties of known paper towels by incorporating polymeric soil adsorbing agents into liquid cleaning compositions used in conjunction with paper towels. There are known liquid cleaning compositions, such as liquid spray cleaners, that comprise a polymeric soil adsorbing agent, for example a copolymer of an acrylic acid and a diquaternary ammonium compound, such as a Mirapol® polymer is commercially available from Rhodia and/or a polyethyleneimine polymer, such as a Lupasol® polymer is commercially available from BASF Corporation. Such liquid cleaning compositions are designed to aid in the removal of soil from various soil laden surfaces, including mirrors, when the liquid cleaning compositions are applied to such surfaces in a liquid form resulting in a soil laden fluid that is capable of being absorbed by a paper towel. In addition, it is known that such liquid cleaning compositions may be applied directly to an article of manufacture, such as a paper towel, by a user immediately before contacting a soil laden surface with the liquid cleaning composition-treated paper towel. Further, it is known that such liquid cleaning compositions may be applied to an article of manufacture, such as a wipe during the wipe's manufacturing process to produce a wet wipe. Further yet, it is known that a dry substrate comprising an impregnated soil adsorbing agent may be moistened and/or dipped into a liquid, such as a liquid cleaning composition, prior to use in order to apparently activate the soil adsorbing agent.
As can be seen from above, formulators in the past apparently believed that soil adsorbing agents, particularly soil adsorbing agent polymers, needed to be present in a liquid, such as in a liquid cleaning composition alone or as part of an article of manufacture, such as a wipe or other substrate, in order to be effective in adsorbing soil.
However, consumers desire dry articles of manufacture (less than 30% and/or less than 20% and/or less than 15% and/or less than 10% and/or less than 5% moisture by weight of the article of manufacture) that exhibit superior soil adsorbing properties compared to known articles of manufacture.
It is believed that adsorption of soil by an article of manufacture, such as a dry fibrous structure, is a better mechanism for soil removal and/or retention than absorption of a soil laden liquid.
One attempt at an article of manufacture that exhibits better soil adsorption properties compared to known articles of manufacture, such as known paper towels, includes a dry wipe that has been impregnated with a polycationic polymer, for example a polyethyleneimine, such as Lupasol®, which is available from BASF, which exhibits a charge density at pH of 4.5 of greater than 10 meq/g; namely +17.8 meq/g. The soil adsorption properties and/or mirror cleaning properties of the dry wipe containing Lupasol® fall well short of consumers' needs and desires.
In addition, almost 25 years ago another attempt at an article of manufacture that exhibits better soil adsorption properties compared to known articles of manufacture at the time includes an article of manufacture that has been impregnated with a cationic polyacrylamide soil adsorbing agent. Such an article of manufacture was taught as requiring a liquid composition, such as a liquid cleaning composition to be added to and/or present on the article of manufacture before using the article of manufacture to clean soil laden surfaces.
In addition to the above uses, suppliers of polyacrylamides such as HyChem, Inc. have provided polyacrylamide polymers to paper manufacturers as retention aids for cellulose fines and/or filler particles and as drainage aids for use in the wet-end of a papermaking machine. For this application, the supplier instructs the manufacturer to prepare dilute aqueous solutions (less than about 0.2% active) where the polymer solutions are permitted to age resulting in the uncoiling of the high molecular weight polyacrylamide chains present in the solutions. Addition rates recommended by the suppliers are less than about 0.5 lb/ton active to avoid overflocculation of the paper sheet causing poor formation. However, such wet-end uses of polyacrylamides do not significantly improve the soil adsorption of the resulting paper made by such processes. In addition, suppliers like HyChem, Inc. typically supply such polyacrylamides in water or water-in-oil inverse emulsions that are made up by adding the neat polymer into a vortex of a stirred tank of water to prepare a solution of 1% concentration (as is). Aging for 30-60 minutes is recommended, followed by in-line dilution to 0.1% or less to invert the emulsions, as is recommended by the suppliers.
In light of the foregoing, it is clear that there has existed a long felt, unmet need for an article of manufacture, such as a fibrous structure, more particularly a dry fibrous structure, that exhibits superior soil adsorption properties and/or mirror cleaning properties and/or absorption properties compared to known articles of manufacture.